Terbuthylazine and desethylterbuthylazine: Recent occurrence, mobility and removal techniques

Abstract

The herbicide terbuthylazine (TBA) has displaced atrazine in most of EU countries, becoming one of the most regularly used pesticides and, therefore, frequently detected in natural waters. The affinity of TBA for soil organic matter suggests prolonged contamination; degradation leads to the release of the metabolite desethylterbuthylazine (DET), which has higher water solubility and binds more weakly to organic matter compared to the parent compound, resulting in higher associated risk for contamination of groundwater resources. Additionally, TBA and DET are chemicals of emerging concern because of their persistence and toxicity towards aquatic organisms; moreover, they are known to have significant endocrine disruption capacity to wildlife and humans. Conventional treatments applied during drinking water production do not lead to the complete removal of these chemicals; activated carbon provides the greatest efficiency, whereas ozonation can generate by-products with comparable oestrogenic activity to atrazine. Hydrogen peroxide alone is ineffective to degrade TBA, while UV/HO advanced oxidation and photocatalysis are the most effective processes for oxidation of TBA. It has been determined that direct photolysis gives the highest degradation efficiency of all UV/HO treatments, while most of the photocatalytic degradation is attributed to OH radicals, and TiO solar-photocatalytic ozonation can lead to almost complete TBA removal in ∼30 min. Constructed wetlands provide a valuable buffer capacity, protecting downstream surface waters from contaminated runoff. TBA and DET occurrence are summarized and removal techniques are critically evaluated and compared, to provide the reader with a comprehensive guide to state-of-the-art TBA removal and potential future treatments.

Assessment of Environmental Pollution and Human Exposure to Pesticides by Wastewater Analysis in a Seven-Year Study in Athens, Greece

“…For instance, cyproconazole is approved as both plant protection and biocidal active substance, while the environmental occurrence of anabasinewhich is not registered under any of the three regulations (plant protection, biocides and REACH)-can be related to tobacco products, based on literature data [35,36]. In addition, the detection of atrazine degradation products is attributed to the high atrazine application in the past and its high persistence in soils [37]. Furthermore, fluconazole is not registered under any of the three regulations, but it is known to be used as antifungal medicine, and climbazole is registered under REACH and used in cosmetics and personal care products.…”

Screening and Distribution of Contaminants of Emerging Concern and Regulated Organic Pollutants in the Heavily Modified Guadalhorce River Basin, Southern Spain

“…Terbuthylazine is a very weak base (pK a = 2). Thus, a non-ionic species exists over nearly the entire pH range and its sorption is dominated by hydrophobic partitioning to sorbent organic matter (log K ow = 3.4 [34]). In fact, its persistence has been partly attributed to the strong adsorption capacity on humic substances [35,36].…”

Sorption Properties of Specific Polymeric Microspheres towards Desethyl-Terbuthylazine and 2-Hydroxy-Terbuthylazine: Batch and Column Studies

“…TBA mineralization and transformation rely on two processes—chlorohydrolysis, with associated depletion of the chlorine atom or N-dealkylation of the side chains of the s-triazine ring. The main degradation pathways of TBA in the soil are presented in [ 13 ]. Depending on the microbial activity, metabolites such as desethyl-terbuthylazine, hydroxy-terbuthylazine, desethylhydroxy-terbuthylazine, diamino-chlorotriazine), desbutylhydroxy-terbuthylazine, amino-dihydroxy-triazine may be formed.…”